Note: Descriptions are shown in the official language in which they were submitted.
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Clear Fabric Softener Formulations
The invention relates to fabric softener formulations based on one or more
cationic surfactants and at least one further component, which give the
overall
formulation a transparent and clear appearance.
Over the course of time, the laundry detergent industry has developed fabric
softener formulations with improved rewetting capacity, high stability and a
good soft handle. The great majority of these formulations enter the market as
aqueous dispersions. Examples of the formulation of dispersions are described,
inter alia, in DE 37 20 331, DE 42 03 489, and EP 0 413 249.
The formulations prepared in accordance with the specifications given therein,
however, require large amounts of energy for their preparation and tend toward
severe fluctuations in viscosity, especially at high storage temperatures.
Furthermore, it is known that agglomerates in fabric softener dispersions lead
to
spotting on the treated textiles.
US-A 5,545,340 describes homogeneous fabric softener formulations which
comprise mixtures of a solid quaternary ammonium compound in a dispersing
aid and of a liquid quaternary ammonium compound in a dispersing aid, and
also a liquid carrier material, and in which fatty acids having a defined
cis/trans
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ratio to the iodine number are used to prepare the quaternary ammonium
compound. These fabric softener formulations, however, do not form clear
solutions.
Against the background of heightened esthetic awareness, a prejudice has
become established against the disperse fabric softener formulations. Among
consumers, an increasing requirement is noted for formulations with a
naturally
clear appearance.
Flowable, highly concentrated and clear fabric softener formulations have
already been described, as for example in DE 33 14 677, DE 36 08 093.
The highly concentrated products described therein, containing generally > 35%
of quaternary fabric softener base materials, have the disadvantage, however,
that these formulations are difficult to dilute with water and/or that, during
the
rinsing of this highly concentrated formulation in the dispenser drawer of the
washing machine, gels of poor solubility in water are formed, and uniform
treatment of the textile is not ensured. Furthermore, with these highly
concentrated fabric softeners, instances of overdosing are frequent, leading
to
spotting on the fabrics thus treated.
It was an object of the present invention, therefore, to avoid these
disadvantages of the prior art and to provide fabric softener formulations
whose
activity spectrum is at least equal to that of the comparable prior art
products
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but which additionally possess a clear and transparent appearance, whose
preparation can be carried out at reduced energy consumption, and whose
handling ensures a trouble-free application among the end users.
It has now been found that fabric softener formulations consisting
predominantly of cationic surfactants and 5-30% by weight, based on overall
formulation, of a further compound meet these requirements.
The invention accordingly provides clear and transparent fabric softener
formulations comprising
(A) 15 to 35% by weight of at least one quaternary ammonium compound of the
general formula (I):
R4 +
[H3C . / 2 (~)
R H2C-CH-O-R
I5
(B) 5 to 30% by weight of at least one compound of the general formula (II):
Rs-(C'=H2)a-O(-CH2-CH(R4)-O-)nH (II)
wherein:
R is -CHs, -CH2-CH(R4)-OR' or -CH2-CH(R5)-OR2, in which R4 and R5 are
identical or different, and are H or -CH3;
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R' and R2 are each independently H or -C(O)-R3, in which R3 is an
optionally-substituted hydrocarbon radical having 13-19 carbon atoms and
containing at least one double bond; with the provisos that: when R is not
CH3, R' and R2 are both H at least 1 to 1.4 times; and when R is CH3, R'
and R2 are H at most 0.4 times;
R6 is a phenyl radical optionally containing Cti-4 alkyl groups, or a
branched alkyl radical having 3 to 6 carbon atoms;
ais0or1;
n is 2.5 to 8; and
A" is an anion of a quaternizing agent;
(C) 0.5 to 18% by weight of customary auxiliaries and additives; and
(D):17 to 79.5% by weight of water.
Preferably, the compounds of the general formula (1) are prepared by
esterifying
at least one alkanolamine compound from the group methyldiethanolamine,
methylethanolisopropanolamine, methyldiisopropanolamine, triisopropanolamine
and triethanolamine, with fatty acids, followed by quaternization.
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Advantageously, the compounds of the general formula (I) are prepared by
esterifying alkanolamines and fatty acids in a molar ratio from 1:1.6 to 1:2,
followed by quaternization.
5 The component (B) preferably includes an exthoxylated or propoxylated
phenol,
benzyl alcohol, isopropanol or butanol, or a mixture thereof, with a degree of
alkoxylation of 2.5 to 3.5.
The quaternary compounds of the general formula (I) that are used in
accordance with the invention are prepared in accordance with the processes
which are common knowledge in this field, by esterification of alkanolamines
such as triethanolamine (TEA), methyldiethanolamine (MDEA),
methyldiisopropanolamine (MDIA), methylethanolisopropanolamine (MEIPA),
triisopropanolamine (TIPA) with fatty acid, followed by quaternization.
Particularly widespread are ester compounds based on triethanolamine, such
as N-methyl, N,N-bis(beta-C14_l$ acyloxyethyl), N-beta-hydroxyethylammonium
methosulfate), which are sold under trade names such as TETRANYL AT 75
(trademark of KAO Corp.), STEPANTEX VRH 90 (trademark of Stepan
Corp.) or REWOQUAT WE 18 (trademark of Witco Surfactants GmbH).
Fatty acids used for the esterification or transesterification are the
monobasic
fatty acids that are customary and known in this field, based on natural
vegetable or animal oils with 6-22 carbon atoms, especially with 14-18 carbon
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atoms, such as oleic acid, linoleic acid, linolenic acid, and especially
rapeseed
oil fatty acid, soybean oil fatty acid, sunflower oil fatty acid, tall oil
fatty acid,
which may be used alone or in a mixture in the form of their glycerides,
methyl
or ethyl esters, or as the free acids. In principle, all fatty acids with
similar chain
distribution are suitable.
The proportion of unsaturated fractions in these fatty acids and fatty acid
esters
is adjusted - where necessary - to a desired iodine number by means of the
known catalytic hydrogenation processes, or is obtained by blending fully
hydrogenated with unhydrogenated fatty components.
The iodine number, as a measure of the average degree of saturation of a fatty
acid, is the amount of iodine absorbed by 100 g of the compound in order to
saturate the double bonds.
Preference is given in accordance with the invention to fatty acids having
iodine
numbers in the range from approximately 40 to 160, but especially rapeseed oil
fatty acids, sunflower oil fatty acids, soybean oil fatty acids, and tall oil
fatty
acids having iodine numbers in the range from approximately 80 to 150. They
are commercially customary products and are sold by different companies
under their respective trade names.
The esterification or transesterification is conducted in accordance with
known
processes. In these processes, the alkanolamine is reacted with the amount of
fatty acid or fatty acid ester corresponding to the desired degree of
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esterification, in the presence if desired of a catalyst, e.g. methanesulfonic
acid,
under nitrogen at 160-240 C, and the water of reaction which forms, or the
alcohol, is distilled off continuously, it being possible if desired to reduce
the
pressure in order to complete the reaction.
For the preparation of the esters, in a first stage the fatty acids and the
alkanolamine are reacted in a ratio such as to result, with a view to the
desired
performance properties of the end products, in a degree of esterification of
from
1.6 to 2.0; in accordance with the invention, particular preference is given
to a
degree of esterification of from 1.8 to 2Ø The compounds prepared in this
way
are technical reaction mixtures, present predominantly as diesters.
The subsequent quaternization also takes place in accordance with known
processes. In accordance with the invention the procedure is such that the
ester, with or without the use of a solvent, preferably isopropanol, ethanol,
1,2-propylene glycol and/or dipropylene glycol, is admixed at 60-90 C with
equimolar amounts of the quaternizing agent, with stirring, under
superatmospheric pressure if desired, and the completion of the reaction is
monitored by checking the total amine number.
Examples of the quaternizing agents used are organic or inorganic acids, but
preferably short-chain dialkyl phosphates and dialkyl sulfates such as, in
particular, dimethyl sulfate, diethyl sulfate, dimethyl phosphate, diethyl
phosphate, short-chain halogenated hydrocarbons, especially methyl chloride.
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For the preparation of the quaternary ammonium compounds in accordance
with general formula (I), fatty acids set out below were used.
Fattv acid I (FA I)
Oleic acid having an acid number of 198-204, an iodine number of
approximately 95 and a carbon chain distribution of
<C16 about 4%
C16 about 5%
C16' about 5% monounsaturated)
C17 about 1 %
C18 about 2%
C18' about 70%
C18" about 12% ("diunsaturated)
>C18 about 2%
Fatty acid II (FA II)
Rapeseed oil fatty acid having an acid number of 196-204, an iodine number of
approximately 98 and a carbon chain distribution of
<C 16 about 2%
C16 about 5%
C16' about 1 %
C17
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C18 about 3%
C18' about 73%
C18" about 14%
>C18 about 2%
Fatty acid III (FA 111)
Tall oil fatty acid having an acid number of 190-198, an iodine number of
approximately 150 and a carbon chain distribution of
C16 about 1%
C16' -
C17 -
C18 about 2%
C18' about 37%
C18" about 60%
>C18 about 1 %
As examples of the quatemary ammonium compounds in accordance with
formula (I), the following compounds were used:
Component A1: TEA : FA I = 1: 1.75
Component A2: TEA : FA I I = 1: 2.0
Component A3: MDEA : FA I = 1: 1.85
Component A4: MEIPA: FA II = 1: 1.9
Component A5: MDIA: FA III = 1: 1.8
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Components Al - A5 were quaternized with dimethyl sulfate and contained
10% by mass of isopropanol as solvent. The references below to components
A' to A5 denote these quaternized compounds.
5
Component B1: R6 = phenyl; R4 = H; n = 4
Component B2: R 6 = i-C4H9 (about 60%)*; n = 0
Sold under the trade name Isanol (Biesterfeld, Hamburg)
Component B3: R6 = I-C4H9 (about 60%) ; R4 = H; n = 2.7
Component B4: Rs - i=C4H9 (about 60%)'; R4 = CH3; n = 2.7
Also used as component B are alkoxylated phenols, which may contain one or
more alkyl substituents, such as, for example, ethoxylated and/or propoxylated
phenol, o/m/p-cresol, thymol, p-tert-butyl-phenol, benzyl alcohol. In
accordance
with the invention, it is also possible to use optionally alkoxylated branched
short-chain alcohols having 3 to 6 carbon atoms, such as isopropanol, butan-
2-ol, 2-methylpropan-l-ol, 3-methylbutan-l-ol, 2-methylbutan-l-ol, and their
alkoxylation products.
The degree of alkoxylation is from 2.5 to 8, preference being given in
accordance with the invention to technical mixtures having an average degree
of
alkoxylation of 2.5 to 3.5. The compounds of component B may
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be employed as a mixture with one another and/or together with one another in
amounts of about 5 to 30% by weight, based on the overall mixture, preferably
in amounts from 10 to 25% by weight.
The fabric softeners are prepared by emulsifying or dissolving the quaternized
compounds A' - A5, together with the use of compounds of the general formula
B, by introducing the respective individual components into water, with
stirring.
In this context it is possible in principle to employ the procedures which are
customary in this field.
In accordance with the invention, a procedure is followed in which water at
room temperature is introduced initially, and, with effective stirring, first
the dye
solution, then any antifoam emulsion required, and, finally, the softener and
component B), as a mixture or in any desired order, are introduced with
stirring.
This is followed by the addition of perfume oil and, if desired, a certain
amount
of an electrolyte solution, in order to reduce the viscosity of the finished
formulation. The fabric softeners of the invention may comprise the stated
components within the limits which are customary in this field, such as, for
example, from 15 to 35% by weight of the compounds of the general formula A;
5 to 30% by weight of at least one of the compounds of the general formula B;
from 0.5 to 18% by weight of one or more of the customary auxiliaries and
additives such as, for example, from 0.05 to 1 % by weight of dyes, from 0.05
to
1% by weight of preservatives, from 0.1 to 12% by weight of short-chain
alcohols/diols having 2 to 6 carbon atoms, from 0.1 to 1% by weight of
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defoaming agents, and also, in particular, from 0.1 to 1.5% by weight of an
alkali metal salt and/or alkaline earth metal salt; from 0.1 to 1.5% by weight
of
perfume oil, and the remainder to 100% by weight (ad 100) of water.
Like the fabric softeners belonging to the known prior art, the fabric
softeners of
the invention are added in the last rinse cycle following the actual washing
operation. Depending on the area of application, the concentration in which
they are employed, following dilution with water, is within the range from 0.1
to
g of fabric softener per liter of treatment liquor.
Examples:
General instructions for preparina clear fabric softener formulations:
Demineralized water is initially introduced at room temperature, the dye
solution
is added, and the quaternary ammonium compound (quat; component A) is
mixed slowly into the water phase with continual stirring. Subsequently,
component B is added with stirring to the mixture of water and quat, until it
forms a clear solution at 20 C. This formulation is then cooled to 4 C, and
must
be clearly transparent at this temperature. If necessary, an additional
quantity
of solubilizer B is introduced with stirring until the mixture is clear at 4
C. At the
same time as, or before or after, the addition of component B, alcohols,
preferably glycols with boiling points > 120 C, may be incorporated into the
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reaction mixture with stirring in order to increase the flash point of the
finished
formulation.
Subsequently, the perfume oil is added with stirring at room temperature and,
if
desired, mineral salts are added in order to adjust the viscosity in the case
of
highly viscous solutions, so as to improve the stirrability and flowability of
the
mixture.
Mineral salts which may be used comprise in particular the chlorides of alkali
metals or alkaline earth metals in amounts from about 0.1 to 1.5% by weight,
preferably in the form of their aqueous solutions with a strength of from 10
to
30%, in particular an aqueous calcium chloride solution.
Example 1:
Water 47.4 parts by mass
Dye* 0.8 part by mass
Component Al 30.6 parts by mass
Component Bl 18.0 parts by mass
Product is clear at 20 C
Propylene glycol 2.0 parts by mass
Product is clear at 4 C
Perfume oil** 0.8 part by mass
Dye*: 1% strength solution of SANDOLAN Walkblau NBL 150 from
Sandoz
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Perfume oil**: Fragrance D 60515 W from Haarmann and Reimer
GmbH
Example 2:
Water 47.4 parts by mass
Dye* 0.8 part by mass
Component A4 30.6 parts by mass
Component B 1 22.0 parts by mass
Product is clear at 20 C
Component B2 2.0 parts by mass
Product is clear at 4 C
Perfume oil** 0.8 part by mass
Example 3:
Water 59.4 parts by mass
Dye* 0.8 part by mass
Component A3 30.6 parts by mass
Component B2 10.0 parts by mass
Perfume oil** 0.8 part by mass
CaCl2 solution*** 1.0 part by mass
Product is clear at 20 C and at 4 C
CaCl2 solution***: 25% by weight in water
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Example 4:
Water 51.4 parts by mass
Dye * 0.8 part by mass
5 Component A4 30.6 parts by mass
Component B2 6.0 parts by mass
Hexylene glycol 12.0 parts by mass
Perfume oil** 0.8 part by mass
Product is clear at 20 C and at 4 C
Example 5:
Water 44.9 parts by mass
Dye * 0.8 part by mass
Component A2 30.6 parts by mass
Component B3 12.5 parts by mass
Hexylene glycol 12.0 parts by mass
Perfume oil** 0.8 part by mass
Product is clear at 20 C and at 4 C
Example 6:
Water 55.4 parts by mass
Dye * 0.8 part by mass
Component Al 30.6 parts by mass
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. , ..
Component B4 10.0 parts by mass
Component B2 6.0 parts by mass
Perfume oil*" 0.8 part by mass
Product is clear at 20 C and at 4 C
Example 7:
Water 46.4 parts by mass
Dye 0.8 part by mass
Component A5 30.6 parts by mass
Component B4 13.0 parts by mass
Dipropylene glycol 5.0 parts by mass
Perfume oil** 0.8 part by mass
Product is clear at 20 C and at 4 C
